Safety device for automobile lifts



A Dec. '5, 1933. 'c. F METZ ET AL A1,938,191

ASAFETY DEVICE FOR AUTOMOBILE LIFI'S Filed June 1'7, 1931 Y Y 771/51@ Arromvfrs.

Patented Dec. 5, 1933 1,938,191 v SAFETY DEVICE FoRAUToMo'BmE LIF'rs Claude F. Metz and Henry MiesnerSt..Lou s, Mo. v Application June 17, 1931. Serial No. 1545,051)

' s claims. (o1. zar-.93)

This invention relates to safety devices for preventing accidental descent of lifting devices, particularly those intendedv for use in lifting automobiles for purposes of inspection, lubrication or repair. The principaljobject of the present invention is to provide an efcient safety device that is simple, compact and is not likely to get out of repair; and to provide for the easy insta-llation and operation of said device. This invention consists inthe parts and combinations of parts hereinafter described and claimed.

In the accompanying drawing, which forms part of the, specication and wherein like symbols refer to like parts wherever they occur, Fig. 1 is a side elevation of a portion ofan auto- Ymobile lift provided with a safety device embodying my invention,

Fig. 2 is a horizontal cross-section on the line 2-2 in Fig. 1, l

Fig. 3 is an enlarged side elevation of the safety device and the adjacent portion of the plunger ofthe lift, the adjacent portions ofthe base and cylinder of said lift being shownl in vertical section; and V f Fig. 4 is a vertical longitudinal section on the line 4-'4"in Fig. 2.

Referring to the accompanying drawing, a safety device embodying our invention is show-n applied to a lifting device of the kind used for raising automobiles to facilitate inspection, lubrication or repair thereof. Such automobile lift, of which only a portion is shown, comprisesvan upright cylinder 1 mounted in a suitable base 2 and a vertically movable fluid-operated plunger 3 working in said cylinder and provided at its up- Y per end with the usual platform for supporting the automobile.

In order to prevent accidental descent of the automobile lift during the ascent thereof and in' 40 its raised position, the automobile lift is provided with a safety device that surrounds the'vertically f movable plunger 3 adjacent 'to the upper end lof the cylinder 1 therefor. Said safety device com;

prises a'base memberin the form of a ring 4 that surrounds the plunger. 3 Cand is provided with radial lugs 5 that are preferably bolted to a ange 6 on the upper end of the cylinder l. The fixed base member of the safety device is provided with a downwardly tapering central conical openof thevertically movable plunger 3 so as Ato provide an annular space between the latter andsaidconical opening. Mounted' to'rotate Yfreely in a cage 8, which surrounds the plunger 3 of the lift, is a circular series of annularly spaced balls' ing 7, whose diameter is larger than the diameter' '9 adapted to seat within the central-opening 7 in the base ring 4. By thisv arrangement, when the lift is raised, the balls 9 tend to move upwardly v with the plunger B toward the large end of the conical opening '7 in the base ring 4 andthus do e0 not interfere with the upward movement of said plunger. If, however, the lifting means should fail during the ascent of the lift or after it has reached thefupper limit of its movement and thus leave the plunger unsupported, the tendency for the plunger to descend will force the balls 9 downwardly towards the small end of the conical opening 7 in the base ring 2, thereby causing said balls to move inwardly in the cage and wedge: tightly between said plunger and the wall of said conical opening and thus prevent descent of the plunger. The amount of play required to allow the balls to rotate freely in the cage is sufficient to permit said balls to be pressed inwardly against the plunger. The base ring 4 is provided with a series 75 of annularly spaced upstanding lugs l0 that project above the ball retaining `cage 8 and serve to prevent the platform of the liftfrom bearing on said cage when the lift is in its lowered position.

When it is desired to lower" the lift, the safety 30 device is released by means of an operating cable 11 which passes around rollers 12 mounted on the base ring 4 land has its end secured to a vpin 13 that vprojects radially from the upper edge of the ball retaining cage .8. B/y this arrangement, the retaining cage 8 may be partially rotated by the pull o n the operating cable 11. The retaining cage is provided with a series of annularly spaced lugs 14 which depend from a'lange 15 at the upper edge thereof and co- 90 operate with notches 16 formed in the upper edge of the base ring 4. Each lug 14 is normally held in abutting relation with one end of a notch 16 by means of a coil spring 1'( which has one end anchored to the base ring 4 and the other 95 end. connected to the pin 13 to which the operating cable 11 is secured. The lower surface of each lug 14 and the bottom surface of the notchy 1Q cooperating therewith are provided with inclined surfaces y18 and 19, respectively, which 100 serve as cam faces for forcing the c age 8 upwardly when said surfaces are brought into contactY by partially rotating the. retaining cage against the tension of the coil springlrl.v By this arrangement, the balls 9 may 'be movedup- 105 wardly in the conical opening 7 in the basev ring far enough' to prevent them from interfering with the downward movement of the plunger 3.

' When` the operating Acable 11 is released, the ball retaining cage 8 is automatically returned to ,110

operative position by The hereinbefore means of the coil spring l'l. described safety device has can be easily installed and is not likely to get out, of repair. descent of the lifting device at any pointof its upward movement; and it may be readily rendered inoperative to permit the lift to descend by a-pull on the operating cable.

Obviously, the hereinbefore described construction admits of considerable modification without departing from the invention. Therefore, we do not wish to be limited to the precise details lof construction shown and described.

What we claim is: 1. A lifting mechanism comprising a vertical.- ly movable member, a stationary member provided with a downwardly tapering conical opening through which said member works, wedgin`g members interposed between said vertical movable member and said conical opening for preventing accidental descent of said vertically movable member, a cage for said wedging members, said cage being rotatable about the vertimovable plunger, a

and a lug on said retaining cage .cal opening through cal axis of said vertical movable member, and means for raising said cage to render the wedging members inoperative, said raising means comprising cooperating cam surfaces 'on said cage and on said stationary member, respectively. 2. A lifting mechanism comprising a vertically movable plunger, a stationary member provided with a downwardly tapering conical opening vthrough which said plunger works, a vseries of balls surrounding said plunger and fitting within the conical opening in said stationary member, a cage for said balls, and means for raising said cage in said opening, said means comprising a cam surface on said stationary member and a lug on said retaining cage adapted to cooperate with said cam surface.

3. A lifting mechanism comprising a vertically stationary member provided with a downwardly tapering opening through which saidplunger works, a series of balls surrounding said plunger and fitting within the downwardly tapering `opening in said stationary member, a cage for said balls, and means for raising said cage in said opening, said means comprising a cam surface on said stationary member adaptedy to cooperate with said cam surface, aspring for normally holding said lug out of contact with said cam surface, and a vcable connected to said/cage for moving the lug thereof into contact with said cam surface on said stationary member.

.4. A n' automobile lift comprising a vertically movable cylindrical plunger, a stationary base ring'providedvwith a downwardly tapering coniwhich said plunger works, a circular series .of wedging members interposed between said vertically movable plunger and said conical `aening for preventing accidental descent of said vertically movable plunger, a rotary and vertically movable cage surrounding .said verticallymovable plunger and supporting said circu- It operates to prevent accidental` lmovable plunger, a

` surface lar series of wedging members, and means for raising said cage relative to` said conical opening to render said wedging members inoperative, said meanscomprising cooperating cams on said cage and said base ring adapted to be brought` into engagement by rotation of said cage.

5. An automobile' lift comprising a vertically stationary base ring provided with c a downwardly tapering conical opening through which' said plunger works, vertically movable wedging means interposed between said vertically movable kplunger and said conical opening for preventing accidental descent of said vertically movable plunger, andA means for raising said wedging means in said conical opening to render said wedging means inoperative, said raising means comprising cooperating cam surfaces on said vertically movable wedging means and on said stationary base ring, respectively.

6. An automobile movable `cylindrical plunger, a stationary base ring provided with a downwardly tapering conical opening through which said plunger works, a circular series of balls surrounding said plunger and adapted to engage the periphery thereof and the conical wall of the opening in said base ring, an annular retaining cage for said series of balls, and means for raising said cage to move the balls therein out of contact with the surface of said conical opening.

7. An automobile lift comprising a vertically movable plunger, a stationary base ring provided with a downwardly tapering lconical opening through which said plunger works, a circular series` of balls surrounding said plunger and adapted to fit between the periphery thereof and the conical wall of the opening in said base ring, a4 retaining cage for said series of balls, means for raising said cage in said conical opening, said raising means comprising a lug on said cage adapted to cooperate with an upwardly inclined on said base ring, a spring for normally holding said lug out of engagement withsaid inclined surface, and means for rotating said cage to bring the lug thereof in contact with the upwardly .inclined surface of said base ring.

removal with said annular cage as a unit, and

means for raising said annular cage to move the kcircular series of Iballs carried thereby out` of contact with the surface of said conical opening.

CLAUDE F. METZ. HENRY lWIESNER.

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